pi-lens/rules/tree-sitter-queries/python/exit-signature-check.yml

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# __exit__ Signature Check
# Detects __exit__ methods without proper parameters (type, value, traceback)
id: exit-signature-check
name: __exit__ Missing Parameters
severity: error
category: reliability
defect_class: correctness
inline_tier: blocking
language: python

message: "__exit__ should accept type, value, and traceback arguments"

description: |
  The __exit__ method in context managers must accept exactly 4 parameters:
  self, exc_type, exc_value, and traceback.
  Missing parameters will cause a TypeError when an exception occurs.

  ✅ FIX: Include all required parameters

  ```python
  class MyContext:
      def __exit__(self, exc_type, exc_value, traceback):
          if exc_type:
              print(f"Error: {exc_value}")
          return False  # Don't suppress
  ```

query: |
  (function_definition
    name: (identifier) @NAME (#eq? @NAME "__exit__")
    parameters: (parameters
      (_) @SELF
      . (_) @PARAM1?
      . (_) @PARAM2?
      . (_) @PARAM3?))

metavars:
  - NAME
  - SELF
  - PARAM1
  - PARAM2
  - PARAM3

post_filter: exit_params_insufficient

tags:
  - reliability
  - python-specific
  - context-manager

examples:
  bad: |
    class MyContext:
        def __exit__(self):  # BAD - missing parameters
            pass
        
        def __exit__(self, exc_type):  # BAD - only one param
            pass

  good: |
    class MyContext:
        def __exit__(self, exc_type, exc_value, traceback):  # GOOD
            if exc_type:
                return False

has_fix: false